Having computer issues with my 05 Suburban

I brought my truck to friendly Chevrolet about 4 weeks ago and they told me I needed a new ECM ($600). So I decided to go the used route for $35 and have them reflash it. Two days later I bring it back because it's running really rough and they tell me water keeps getting into the connections and the seal is bad. They say you can't buy just the seal and I have to replace the whole connector and harness ($1500 parts and install). They blew it out and put some dielectric grease in it and sent me on my way. Two weeks later the truck won't even start. So I tow it to main motors and they say the ECM is bad again. Try another used one and truck runs now but doesn't like to idle at stop signs and red lights when it's in gear but will idle really low in neutral and park. Obviously it's still computer related but it's not throwing check codes. Does anyone have experience with something like this or know anyone who knows how to fix it that isn't a dealership? Thanks for the help! Can call or text Brandon at 763-234-682two with any help.

6 Answers

Hi Brandon, my advice would be get a rebuilt PCM
(computer) and have it flashed. Flashing a PCM simply
means programming it to your specific vehicle. That's why
they use your vehicle identification number to do it. You
can buy the rebuilt PCM at just about any auto parts store
and have just about any repair facility flash it for you.
HTH. -Jim

That may be the problem. I have
tried two used PCM's and I'm told
that they are still having trouble
communicating with the PCM. That
is why they are saying the wiring
and connector could be bad and
should be replaced ($1500)

I'd be leaning toward the PCM as well. The PCM wiring
and connectors are pretty sturdy. Unless the vehicle is
pretty old, which it's not, has been in an accident, or you've
had trouble with "critters" I'd say it's a safe bet the wiring
is good. HTH. -Jim

Yeah, used electrical parts scare me. You don't know what
they've been through. One other thing that I thought of is
check your ground straps and ground wires. The PCM has
to have a good solid ground as well. HTH. -Jim

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